Precipitation Behavior in a Hanks’ Solution on Ca-P-O Films Prepared by Laser CVD

Abstract

Ca-P-O films were prepared by laser CVD using Ca(dpm)₂ and (C₆H₅O)₃PO metal organic precursors. The crystal phase of Ca-P-O films changed depending on deposition temperature (T_dep), total pressure (P_tot), laser power (P_L) and molar ratio of Ca to P (R_Ca/P). β-TCP films in a single phase were obtained in a P-rich and high T_dep region, while HAp films in a single phase were obtained in a Ca-rich and low T_dep region. The β-TCP films had a (220) orientation with an elongated and angular roof-shaped surface texture, whereas HAp films had a (300) orientation with a granular surface texture. Both the β-TCP film and the HAp film had a dense cross section. The Ca-P-O films were immersed in a Hanks’ solution for 6 h to 7 d. Particle-shaped precipitates were observed on the β-TCP and HAp films after 3 d immersion. Needle-shaped precipitates covered the whole surface of HAp film after 7 d immersion.